Collisional Shear Alfvén Waves in Sheared Magnetic Fields

Phys. Fluids 24, 1499 (1981)https://ireap.umd.edu/10.1063/1.8635541981Journal ArticlePlasma, Accelerator, and Nuclear Physics

The structure of the shear Alfvén waves is investigated in a collisional plasma with shear. The fourth‐order equation obtained by combining Ampere’s law and the quasi‐neutrality condition is solved by the method of matched asymptotic expansions for k_⊥ ρ_s≫≪1 to obtain the dispersion relation. A hierarchy of damped, localized modes are found which can have either even or odd parity. The solutions basically have the structure of kinetic Alfvén modes trapped between the two Alfvén cutoffs on either side of the rational surface. The mode damping arises from Ohmic dissipation by electrons near the rational surface. The relation between these modes, microtearing modes, and the Alfvén continuum is discussed.